Deck 30: Lipids

Question 1

How can an unsaturated fatty acid be converted into a saturated fatty acid?

A) hydrogenation
B) hydration
C) ozonolysis
D) hydrolysis

Answer 1

hydrogenation

Question 2

Provide a definition of the term lipid.

A) a compound with a carbonyl group
B) a compound with an aromatic ring
C) a hydrophobic biomolecule
D) a water-soluble compound

Answer 2

a hydrophobic biomolecule

Question 3

Evaluate the following statement: The terpene structure shown is a hydrolysable lipid.

A) True, because it contains an alcohol functional group.
B) False, because alcohol and aldehyde moieties are not hydrolysable.
C) True, because there are three polar groups and only 12 total carbon atoms.
D) False, because there is too much steric repulsion from the alcohol and aldehyde moieties.

Answer 3

False, because alcohol and aldehyde moieties are not hydrolysable.

Question 4

What happens to the melting point in fatty acids as the unsaturation increases?

A) It increases
B) It decreases.
C) There is no direct correlation between unsaturation and melting point.
D) The melting point stays the same.

Question 5

Eicosanoids are derived from what compound?

A) arachidonic acid
B) cyclohexane
C) cholesterol
D) triacyl glycerols

Question 6

What is (are) the basic subunits of terpenes?

A) cyclohexane
B) triacyl glycerols
C) isoprene
D) carbonyls

Question 7

Liquid oils usually have a higher percentage of what component compared to solid fats?

A) oxygen
B) hydrogen
C) unsaturation
D) aromatic rings

Question 8

How many isoprene units are contained in the following molecule?

A) 5
B) 4
C) 3
D) 2

Question 9

Solid fats are generally from what source?

A) vegetables
B) starches
C) legumes
D) animals

Question 10

How many isoprene units are in the following molecule?

A) 1
B) 2
C) 3
D) 4

Question 11

Which of the following compounds is a steroid?

A) A
B) B
C) C
D) D

Question 12

Which of the following is a phospholipid?

A) A
B) B
C) C
D) D

Question 13

What is the main cellular function of a triacylglycerol?

A) signal transduction
B) form cell membranes
C) nerve cell transferal
D) energy storage

Question 14

What is the purpose of vitamin K?

A) energy storage
B) blood clotting
C) photosynthesis
D) hydrogenation

Question 15

Which of the following compounds is not a hydrolyzable lipid?

A) A
B) B
C) C
D) D

Question 16

Which structure represents the lowest energy conformation of a trans-decalin?

A) A
B) B
C) C
D) D

Question 17

Which of the following compounds is not a lipid?

A) A
B) B
C) C
D) D

Question 18

What is (are) the biological precursor(s) for the formation of the steroid skeleton found in cholesterol?

A) cyclohexane
B) squalene
C) triacyl glycerols
D) arachadonic acid

Question 19

What is the first key enzyme required for the synthesis of prostaglandins from arachidonic acid?

A) protein Kinase C
B) synthase
C) transferase
D) COX (cyclic oxygenase)

Question 20

What chemical process causes an oil (such as soybean oil) to become rancid?

A) hydrogenation with hydrogen
B) hydration with water
C) oxidation with molecular oxygen
D) bromination with bromine

Question 21

Which of the following correctly describes waxes?

A) long chain alcohols
B) long chain esters
C) long chain ethers
D) long chain fatty acids

Question 22

Which of the following sequences shows a reasonable series of 1,2-rearrangements as might be found in the biosynthesis of a steroid?

A) A
B) B
C) C
D) D

Question 23

From the statements below, pick out the one that is not correct for fat-soluble vitamins.

A) Fat-soluble vitamins are classified as lipids.
B) Fat-soluble vitamins are a group of biologically active compounds containing 20 carbon atoms.
C) Fat-soluble vitamins are required in small quantities for normal metabolism.
D) Fat-soluble vitamins are stored in fat cells for use when they are needed.

Question 24

Triacylglycerol A yields compound B when treated with excess H₂, Pd-C. Ozonolysis of A affords three molecules of compound C and one molecule of compound D. What is the structure of A? Choices for Triglycerol A:

A) A
B) B
C) C
D) D

Question 25

Which of the following fatty acids has the highest melting point?

A) palmitic acid
B) arachidic acid
C) stearic acid
D) lauric acid

Question 26

Which of the following is not one of the three main categories of hydrolyzable lipids?

A) waxes
B) steroids
C) triacylglycerols
D) phospholipids

Question 27

The stereoselective introduction of the C15 OH group on the $\omega$ side chain of prostaglandins has presented a challenge for synthetic chemists. Recently, Mulzer and co-workers demonstrated a new route in which the $\omega$ side chain is synthesized independently and then attached to the bicyclic counterpart. What is the appropriate sequence of reagents for the following synthesis?

A) (1) PBr₃; (2) Grubbs' catalyst, Reagent X; (3) KOC(CH₃)₃
B) (1) PCC; (2) Ph₃P=CH₂; (3) Grubbs' catalyst, Reagent X
C) (1) PBr₃; (2) Ph₃P=CH₂; (3) Grubbs' catalyst, Reagent X
D) (1) TsCl, pyridine; (2) Grubbs' catalyst, Reagent X; (3) KOC(CH₃)₃

Question 28

Norethindrone is a synthetic steroid that is better than progesterone in suppressing ovulation. What reagents (1-3) are required to convert norethindrone to the derivatives shown below?

A) (1) H₂, Pd-C; (2) (CH₃)₂CHCH₂NH₂, NaBH₃CN; (3) a. O₃, b. Zn, DMS
B) (1) H₂, Pd-C; (2) (CH₃)₂CHCH₂NH₂, mild acid; (3) a. O₃, b. Zn, DMS
C) (1) a. LiAlH₄, b. H₂O; (2) (CH₃)₂CHCH₂NH₂, NaBH₃CN; (3) a. OsO₄, b. NaHSO₃
D) (1) a. LiAlH₄, b. H₂O; (2) (CH₃)₂CHCH₂NH₂, mild acid; (3) a. OsO₄, b. NaHSO₃

Question 29

Which of the following are complex lipids?

A) steroids
B) terpenes
C) waxes
D) protaglandins

Question 30

Sphingomyelins are a major component of the myelin sheath. Damage to the myelin sheath results in such diseases as multiple sclerosis. Which compound below corresponds to a sphingomyelin?

A) A
B) B
C) C
D) D

Question 31

Patchouli alcohol is an example of a terpene. How is this molecule classified?

A) monoterpene
B) diterpene
C) triterpene
D) sesquiterpene

Question 32

What is the result of the oxidation of arachidonic acid with O₂ by cyclooxygenase?

A) It results in the synthesis of prostaglandins, thromboxanes, and prostacyclins.
B) It results in the synthesis of fat-soluble vitamins from sphingomyelins.
C) It results in the synthesis of phosphoacylglycerols.
D) It is an important step in the synthesis of lipids that form the lipid bilayer.

Question 33

Which of the following classes of molecules is not a nonhydrolyzable lipid?

A) steroids
B) terpenes
C) phospholipids
D) eicosanoids

Question 34

Which of the following fatty acids has the lowest melting point?

A) palmitic acid
B) arachidic acid
C) stearic acid
D) lauric acid

Question 35

All except one of the statements below are true about the molecule given. Which statement is not correct?

A) This molecule is a phospholipid and is generally found in fruits, vegetables, fish, liver, and dairy products.
B) This molecule is a phospholipid that composes the main fabric of the insoluble barrier that protects the cell.
C) This molecule contains two fatty acids and has at least one stereogenic center.
D) This molecule is a phospholipid and belongs to the general category of lecithins.

Question 36

Which of the following are simple lipids?

A) steroids
B) terpenes
C) waxes
D) prostaglandins

Question 37

Which of the following fatty acids is not present in natural fats and oils?

A) hexadecanoic acid
B) heptadecanoic acid
C) octadecanoic acid
D) none of the choices

Question 38

Which of the following fatty acids has the lowest melting point?

A) linoleic acid
B) oleic acid
C) arachidonic acid
D) palmitoleic acid

Question 39

Which of the following fatty acids has the highest melting point?

A) linoleic acid
B) oleic acid
C) arachidonic acid
D) palmitoleic acid

Question 40

What is the correct classification of the following compound? CH₃(CH₂)₁₅COOH

A) saturated triglyceride
B) simple lipid
C) wax
D) saturated fatty acid

Question 41

What is the name of the reaction of triglycerides with a base?

A) esterification
B) transesterification
C) ozonolysis
D) saponification